Bagging machine



Nov. 30, 19.65 J. A. HART ETAL 3,220,156

BAGGING MACHINE Filed Dec. 11, 1962. 2 Sheets-Sheet l INVENTORS JOHN A.HA R7 RICHARD M. ANDLQSON are! 4-7741 ms Nov. 30, 1965 J, A. HART ETAL3,220,156

BAGGING MACHINE Filed Dec. 11, 1962 2 Sheets-Sheet 2 press ur/Z edf/ulo/ $0 'urce SO L) $3 a 86 f g w -a4 OI'CSSUf/Zd f/Uld sourceINVENTORS uo/wv A HART RICHARD M. ANDERSON United States Patent3,220,156 BAGGING MACHINE John A. Hart, Longmeadow, and Richard M.Anderson,

Westfield, Mass, assignors to Package Machinery Company, EastLongmeadow, Mass, a corporation of Massachusetts Filed Dec. 11, 1962,Ser. No. 243,762 4 Claims. (CI. 5377) The present invention relates toimprovements in packaging or bagging machines and more particularly toimprovements in that type of machine wherein a pair of draw bars orclamps grip successive portions of a tube of wrapper material at spacedpoints along the length thereof to seal the tube in the forming ofpillow-shaped packages.

The object of the invention is to minimize, if not eliminate, thepossibility of serious injury to the draw bars in the event an articlewithin the wrapper tube is disposed between the draw bars as they closeto clamp and seal the tube.

The particular problem which has been overcome by the present inventionis best illustrated in the packaging of hardware such as screws, hingeplates, and the like. In a vertical type bagging machine, a tube ofwrapper material is formed around a feed or drop tube, through which thearticles to be packaged fall. A transverse seam is formed at the lowerend of this wrapper tube from a previous operation and the articles thenfall to the bottom of the tube. The draw bars then grip the wrapper tubewith considerable force to facilitate the formation of a secondtransverse seal which defines the upper end of the package and the lowerend of the next package. If an item has rebounded between the draw barsor has failed to fall below the draw bars, the closing pressure issuflicient to cause serious damage, necessitating a loss of productionfrom the machine and the expense of repairing or replacing the damageddraw bars.

In accordance with the inventive concepts of the present invention,means are provided for closing the draw bars with a minimum force andthen applying a greatly increased force to the draw bars after they areat least substantially closed. In other words, if an article werebetween the draw bars, they would be held apart by the article and fullclamping pressure would not be applied in that particular machine cycle.Preferably the draw bars are opened and closed by a fluid pressure motorand optional means may be provided for initiating closing movement witha high pressure in order to obtain a faster cycle of operation.

The above and other related objects and features of the invention willbe apparent from a reading of the following description of thedisclosure found in the accompanying drawings and the novelty thereofpointed out in the appended claims.

In the drawings:

FIG. 1 is a diagrammatic view of a bagging machine of the type employingthe present invention;

FIG. 2 is a schematic view of means for opening and closing the drawbars of such machine in accordance with the present invention;

FIG. 3 is a schematic view illustrating a modified embodiment of theinvent-ion which may replace the component-s seen in FIG. 2 below lineAA.

Referring first to FIG. 1, the machine therein shown 3,220,156 PatentedNov. 30, 1965 is essentially the same as in US. Patent No. 3,061,989.Basically, this machine comprises a folder 10 about which a web W ofwrapper material is trained to form a tube T of wrapper material. Themarginal edges of the web W are lapped and sealed by a heat sealing unit12, which forms a continuous longitudinal seam. A feed or drop tube 14is disposed within the tube T. A pair of draw bars 16 and 18 areslidably mounted on a pair of rods 20 which project from a swinging armor bracket 22. The bracket 22 is mounted by links 24 and 26 which inturn are mounted on fixed pins 28 and 30. A link 32 is pivotallyconnected at its upper end to an extension 34 of the bracket 22 and atits lower end to a crank arm 36. The crank arm 36 is connected to ashaft 38 which is rotated from an appropriate power source by a chain40. As is more fully explained in the aforementioned patent, rotation ofthe crank 36 will cause the draw bars 16 and 18 to reciprocate in avertical direction.

Means including a fluid motor 44 (see also FIG. 2) mounted on thebracket 22 are provided for opening and closing the draw bars 16 and 18.These means further include a lever 46 to which the rod of the fluidmotor 44 is pivotally connected. The lever 46 is secured to a shaft 48journaled on the bracket 22. A pair of doubleended levers 50 are alsosecured to the shaft 48. Links 52 extend from the upper ends of thelevers 50 to the front draw bar 20 and links 54 extend from the lowerends of the levers 50 to the rear draw bar 18.

The draw bars are illustrated in their open position. Extension of thepiston rod of motor 44 will rotate shaft 48 in a counterclockwisedirection and with it the doubleended levers 50. This will cause thedraw bars to move towards each other and clamp the tube of wrappermaterial therebetween. With the wrapper tube thus clamped, means areprovided for transversely heat sealing the wrapper tube and thentransversely severing the tube intermediate the heat sealed area as thedraw bars 16 and 18 are moved downwardly. Upon reaching the bottom oftheir stroke, the draw bars open, releasing a completed package and thenmoving upwardly preparatory to a further cycle of operation. Whateverproduct is to be packaged is dropped into the tube 14 at a proper timeso that it will reach the bottom of the wrapper tube T prior to closureof the draw bars 16 and 18.

Again, the constructional details and the specific mode of operation ofthe draw bars may be obtained by referring to the above-mentionedpatent. However, at this point it will be noted that the concepts of thepresent invention, in general aspects at least, will apply equally wellto the more familiar type of vertical bagging machine as exemplified byU.S. Patent No. 1,986,422 of the horizontal type of packaging machine asexemplified by US. Patent No. 2,296,142.

The present application deals more specifically with the manner in whichthe draw bars are closed. The control system shown in theabove-mentioned Patent No. 3,061,989, will again be used as theenvironment of the invention. In that disclosure there is shown a camshaft here indicated by reference character 56 (FIG. 2) which is rotatedin fixed relation to rotation of the crank arm 36 which motivates up anddown movement of the draw bars 16 and 18. Spiral grooved cams 58 and 60are mounted on the shaft 56. Switches 62 and 64 are controlled by thecams 58 and 60 respectively. The switches 62 and 64 are normally closedand are held open by the earns 58 and 60 except for the periods when thegrooves therein are aligned with the actuators for said switches. Thusthe switches 62 and 64 are momentarily closed for a short period of timeduring each cycle of operation.

Pressurized fluid, preferably pressurized air, is conducted from anappropriate source through a conduit 66 and then through conduits 68 and70 to a valve 72. From the valve 72 the pressurized air may be conductedthrough either conduit 74 or 76 to one end or the other of the air motor44. The valve 72 is displaced in one direction by solenoid S-1 and inthe other direction by solenoid 8-2. Solenoid 8-1 is connected in serieswith switch 62 and solenoid S2 is connected in series with switch 64.Both sets of switches and solenoids then being connected across anappropriate power source.

Solenoid S-1 is energized to displace the valve 72 to the positionillustrated some time during the down stroke of the draw bars 18 and 20,or at least before they begin their upward movement. Thus it will seemthat pressurized fluid flows through the conduits 68 and 74 maintainingthe piston of motor 44 in a retracted position with the draw bars openas in FIG. 2. When the draw bars approach the upper limit of theirupstroke, switch 64 will momentarily close, energizing solenoid S-2 andshifting valve 72 toward the right so that air will no longer flow toconduit 74, but will now flow from conduit 70 to conduit 76. It will benoted that a valve 78 is interposed in conduit 70 and maintained in aposition which blocks flow of air from conduit 66 to conduit 70 by asolenoid S-3. Thus, solenoid 8-3 is maintained energized by a normallyclosed switch 80 mounted on a channel member 82 which is secured to thebracket 22. The switch 80 and solenoid S-3- are connected in seriesacross the same power source previously referred to. Pressurized airthus flows through a by-pass conduit 84 and a pressure reducing valve86. Thus low pressure air is provided for projecting the rod of fluidmotor 44 and rotating the shaft 48 in a counterclockwise direction toclose the draw bars 18 and 20. The low pressure provided for thisclosing movement is such that should there be an article disposed withinthe wrapper tube and between the draw bars 18 and 20, the motor 44 willstall rather than apply sufiicient force to damage the draw bars.However, if this undesirable condition does not occur, closing movementwill continue and the upper end of one of the levers 50' will engage theplunger of switch 80 opening that switch and thereby deenergizingsolenoid S3. The valve 78 is a spring loaded valve which is displacedupon deenergization of solenoid S3 to bring its port into alignment withconduit 70, whereupon full pressure will be supplied through conduit 76and greatly increased pres sure will be transmitted to the rod of motor44 to provide the necessary force for draw bars 18 and 20 to obtain aneffective heat seal.

Upon further rotation of the cam shaft 56, switch 62 is momentarilyenergized displacing valve 72 back to the position illustrated, therebyintroducing full line pressure through conduit 68 and 74 to the oppositeend of the fluid motor 44 and thus opening the draw bars. Switch 80again closes to energize solenoid S-3 so that the cycle of operationabove described may again be repeated.

Patent No. 3,061,989, above referred to, gives a more completedescription of the electric control circuit in which the present circuitelements are incorporated. Further detailed description is not deemednecessary for those skilled in the art.

Referring now to FIG. 3, the components therein may replace the elementsbelow line A--A in FIG. 2. It will be seen that switch 80, solenoidsS-l, S-2 and -3, remain the same. Likewise switches 62 and 64 are againcontrolled by cams 58 and 60 to actuate the solenoids S-1 and S2 inproper timed relation. Valve 72 controls flow of air from conduits 68and 70 as above 4 described to the conduit 74 and 76. Likewise thebypass conduit 84 and reducing valve 86 provide for a flow of fluidunder reduced pressure. Also conduit 66 is connected to an appropriatesource of pressurized air or pressurized fluid.

The only difference between the two circuits is. in the provision of asecond switch 88 for controlling the solenoid S3. Thus it will be seenthat switches and 88 are connected in series with solenoid S-3, acrossthe appropriate electrical power source. Switch 88 is controlled by cam90 which is also secured to the cam shaft 56.

The operation of this embodiment is the same insofar as opening movementof the draw bars is obtained by energization of solenoid S-1 displacingthat valve to the illustrated position. When solenoid 8-2 is energizedas above described, switch 88 is open so that solenoid S3 isdeenergized. This means that full line pressure may pass through theconduits 70 and 76 to initiate closing movement of the draw bars. Ashort time later switch 88 is closed energizing solenoid S-3 andpreventing further flow of fluid directly from conduit 66 to conduit 70.Thus, the fluid pressure provided for closing the draw bars during theremainder of their closing movement and particularly during the criticaltime where they might engage and crush an article disposed therebetween,only low pressure fluid is available. If there is no obstruction totheir complete closure, the switch 80 will be opened by one of thelevers 5t) deenergizing solenoid S3 and again permitting full pressureto be transmitted through conduits 70 and 76 to the motor 44 and thusprovide the necessary high pressure for the draw bars 18 and 20 duringthe heat sealing operation.

It will be noted that cam 90 is also a spiral cam but that itsdepression or groove is much wider. In the first instance, the use ofspiral cams enables a timing adjustment by shifting the switches 62 and64 in a direction axially of the shaft 56 as described in theaforementioned Patent No. 3,061,989. Switch 38 would also be adjusted inthe same fashion and preferably would be coupled to switch 64. However,switch 88 must remain energized, at least in this particular circuit,for a greater period of time, until the draw bars are substantiallyclosed, which accounts for the shape of the depression.

Having thus described the invention, what is claimed as novel anddesired to be secured by Letters Patent of the United States is:

1. In combination with a bagging machine of the type wherein articlesare introduced into a continuously formed tube of wrapper material andhaving a pair of clamps for gripping the wrapper tube and forming atransverse seam therein, yieldable means for closing the clamps towardeach other with a relatively low force and means responsive to the drawbars being moved to a contiguous relation for applying a much greaterclosing force to the clamps to complete their closing movement ingripping the wrapper tube.

2. In combination with a bagging machine of the type wherein articlesare introduced into a continuously formed tube of wrapper material andhaving a pair of clamps for gripping the wrapper tube and forming atransverse seam therein, yieldable means for initiating closing movementof the clamps with a relatively strong force, contmuing closing movementwith a relatively low force and means responsive to the draw bars beingmoved to a contiguous relation for applying a much greater closing iorceto the clamps to complete their closing movement 1n gripping the wrappertube.

3. In combination with a bagging machine of the type wherein articlesare introduced into a continuously formed tube of wrapper material andhaving a pair of clamps for gripping the wrapper tube and forming atransverse seam therein, means for reciprocating the clamps lengthwiseof said tube and means including an air motor for closing and openingthe clamps in proper timed relation to their reciprocating movement,said air motor comprising a piston and cylinder to one end of whichpressurized air is directed for closing movement of said clamps, theimprovement which comprises means for directing low pressure air to saidone end of said cylinder during closing movement of said clamps, meansfor detecting closure of said clamps to a contiguous relationship andmeans responsive to actuation of said detecting means for directiug highpressure air to said one end of said cylinder.

4. The combination of claim 3 wherein means are provided for directinghigh pressure air to the said one end of said cylinder for a shortperiod of time when air is first directed to said one end to initiateclosing movement of the draw bars in order that the draw bars may berapidly accelerated in their closing movement.

References Cited by the Examiner UNITED STATES PATENTS 10 FRANK E.BAILEY, Primary Examiner.

TRAVIS S. MCGEHEE, Examiner.

1. IN COMBINATION WITH A BAGGING MACHINE OF THE TYPE WHEREIN ARTICLES ARE INTRODUCED INTO A CONTINUOUSLY FORMED TUBE OF WRAPPER MATERIAL AND HAVING A PAIR OF CLAMPS FOR GRIPPING THE WRAPPER TUBE AND FORMING A TRANSVERSE SEAM THEREIN, YIELDABLE MEANS FOR CLOSING THE CLAMPS TOWARD EACH OTHER WITH A RELATIVELY LOW FORCE AND MEANS RESPONSIVE TO THE DRAW BARS BEING MOVED TO A CONTIGUOUS RELATION FOR APPLYING A MUCH GREATER CLOSING FORCE TO THE CLAMPS TO COMPLETE THEIR CLOSING MOVEMENT IN GRIPPING THE WRAPPER TUBE. 